Pearson clocked 12.35 seconds to triumph ahead of America's Dawn Harper, who was 0.02s behind in a personal best time, and bronze-winning Kellie Wells, also of America. Harper put up a brave defence of her Olympic title, which she won in 12.54s, but ultimately came up just short.

The time Jessica Ennis posted in the 100m hurdles stage of the heptathlon - 12.54s - would have been enough for fourth place.

Victory for world champion Pearson adds another coveted prize to her medal collection, having only managed silver at the Beijing Games four years ago. Britain's Tiffany Porter failed to make the final after finishing fourth in her heat in a time of 12.79 seconds - not enough for a fastest loser spot.

Sanya Richards-Ross was the fastest qualifier in a star-studded line-up for the 200m semi-final, clocking 22.3s. Britain's Margaret Adeoye could only manage seventh in her 200m heat, running 23.28s, and will take no further part in the event, while there was also disappointment for Abi Oyepitan (23.14s).

The final will feature 400m Olympic champion Richards-Ross, 100m champion Shelly-Ann Fraser-Pryce, and defending 200m title holder Veronica Campbell-Brown. However, the most impressive qualifier was two-time silver medallist Allyson Felix.

In the long jump, Britain's Shara Proctor booked her place in the final with a leap of 6.83m, an effort only previously bettered by three British women. Even more impressive was that Proctor hit her mark at the first time of asking.